Measurements of body colors become increasingly important in many technological fields. In the medical field it is important to obtain objective standards for body colors, for example, to obtain diagnostic information about the skin surface. In the conventional colors measuring apparatuses, the light which is radiated from the skin surface of a body point is analyzed in its spectrum by a monochromator and is then compared with given standard spectral value curves to determine the color coordinates. In the case of non-self-luminous objects there must be started from a given illumination type or the primary light spectrum must be included and the re-emission spectrum of the body point be corrected thereon.
Such a spectrometer is known from DE-OS 27 26 606 corresponding to U.S. Pat. No. 4,241,738 which relates substantially to a so-called medical spectrophotometer having a spacer ring at the end where the objective is positioned to measure the color by means of the spectrometry of reflected light, so of the measurement of the re-emission (reflectance) of, for example, a skin surface, in which as a reference a white standard is used alternately. Such a spectrometer enables the determination of the re-emission spectrum of a point of the surface.
With structured surfaces, for example, of a skin surface with moles or of the surface of a mole itself, it is necessary not only to determine a defined point with respect to its re-emission spectrum, but also to determine this information of a plurality of skin surface points. In the ideal case it is desirable to determine the re-emission spectrum of each point of the skin surface. This requires an expensive point-by-point scanning of the surface. Furthermore, in the examination of in certain circumstances malignant moles a contact-free examination is desirable.
A device for measuring and evaluating natural fluorescent spectra of organic tissue surfaces is known from DE-OS 38 15 743 corresponding to U.S. Pat. No. 5,014,707. In the latter device it is suggested for establishing the spectral distribution of fluorescent light of the skin surface to expose same to a light stripe by projection of an image of a slot on the skin surface. This has for its result that a common spectrum is obtained, which spectrum is the average of the spectra of all points of the slot image projected from the light source on the skin surface. As already explained hereinbefore, a desired optical point-by-point scanning of the skin surface is not possible with this device.